The present invention relates to a fuel tank fixing structure for a small-size boat or craft, and more particularly to a fuel tank fixing structure for a saddle-type, small-sized boat or small craft.
As shown in FIG. 8(a), a first exemplary fuel tank fixing structure for a small-size boat is known in the background art in which a pair of tank supporting portions 3, 3 are provided on the bottom portion of an inner wall 2 of a hull 1. A fuel tank (hereinafter simply referred to as a tank) 4 is mounted on the tank supporting portions 3, 3, in a position in which the bottom portion of the tank 4 is sandwiched between the pair of tank supporting portions 3, 3. The tank 4 is fixed to the hull 1 by a belt 5. The belt 5 is fixed to one side of the hull and looped over the top surface of the tank 4 to the other side of the hull (see Japanese Unexamined Patent Publication No. 4-201797).
Further, as shown in FIG. 9, a second exemplary fuel tank fixing structure is known in the background art in which a tank 6 is formed in a shape adapted to the bottom portion of the inner wall 7 of a hull and is sandwiched, positioned and fixed by inner wall side surfaces 8, 8 opposing other (see Japanese Unexamined Patent Publication No. 5-16882).
The above-mentioned fuel tank fixing structures suffer from the following problems and drawbacks. First, the fuel tank is not always positioned and fixed in a stable state, as described hereinafter. Typically, a fuel tank does not always have a high dimensional accuracy after manufacture. For instance, where a fuel tank is manufactured from blow molding of synthetic resin, the dimensional accuracy inevitably becomes very low.
Under such conditions, for example, as shown in FIG. 8(a)-(b), in the structure in which the pair of tank supporting portions 3, 3 sandwich the tank 4, in the case a gap C is produced between the smaller tank 4xe2x80x2 and the supporting portions 3, 3 where the tank 4 is smaller than a predetermined size. As seen in FIG. 8(b), the tank 4xe2x80x2 cannot be accurately positioned and fixed in a stable state.
In contrast, as shown in FIG. 8(c), in the case where the tank 4 is larger than a predetermined size, the larger tank 4xe2x80x3 is pressed by the supporting portions 3 by forces F producing undesirable stresses.
These problems are similarly presented in the structure shown in FIG. 9. In the case where the tank 6 is smaller than a predetermined size, a gap is produced between the small tank and the inner wall surfaces 8, 8. Accordingly, the tank cannot be positioned and fixed in a stable state. In contrast, in the case where the tank 6 is larger than a predetermined size, the larger tank 6 is pressed by the inner wall side surfaces 8 by forces producing undesirable stresses.
The present invention overcomes the shortcomings associated with the background art and achieves other advantages not realized by the background art.
An object of the present invention is to provide a fuel tank structure that permits stable attachment of a fuel tank to a small craft of vessel.
A further object of the present invention is to provide a fuel tank structure that permits stable attachment of the a fuel tank without incurring undesirable stresses in the surface of the fuel tank and surrounding structure.
These and other objects are accomplished by a fuel tank support structure for a small-size boat, the fuel tank support structure comprising a boat hull; a fuel tank mounted on a bottom portion of the hull; a tapered, single projecting portion for positioning formed on either an inner wall of the bottom portion of the hull or on a bottom portion of the fuel tank; a tapered, depressed portion for positioning fitted on the projecting portion and formed on either the bottom portion of the fuel tank or the inner wall of the bottom portion of the hull, the tapered, single projecting portion and the tapered, depressed portion matingly engaging in order to position the fuel tank with respect to the hull; and a space formed between a peripheral wall of the fuel tank and the inner wall of the hull.
Therefore, even if the fuel tank does not have a high dimensional accuracy, the tapered surface of the depressed portion or the projecting portion of the fuel tank is fitted on the tapered surface of the projecting portion or the depressed portion of the hull. The depressed portion or the projecting portion of the fuel tank is then positioned with respect to the projecting portion or the depressed portion of the hull in a stable state.
That is, even if the fuel tank is a little smaller or larger than a predetermined size, the fuel tank is positioned without experiencing undesirable play and unnecessary stresses in the fuel tank. Further, since the space is formed between the peripheral wall of the fuel tank and the inner wall of the hull, even if the fuel tank is a little larger than a predetermined size, no unnecessary stresses are generated in the fuel tank.
As described above, according to the fuel tank support structure for a small-size boat described hereinabove, the fuel tank can be positioned and fixed in a stable state and unnecessary stress are not generated in the fuel tank. Further, even if the fuel is put into the fuel tank to expand the fuel tank, it is possible to keep the fuel tank in a stable, reliably positioned state and to prevent any unnecessary stresses from being generated in the fuel tank.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.